Object reference not set to an instance of an object.

[Jes|er]

I keep getting this Error:

An unhandled exception of type 'System.NullReferenceException' occurred in AdvancedReg.exe

Additional information: Object reference not set to an instance of an object.

With this code: (First Line after comment)

' Delete the three values just added.
        regProduct.DeleteValue("Path")
        regProduct.DeleteValue("MajorVersion")
        regProduct.DeleteValue("MinorVersion")
        ' Delete the Product key, after closing it.
        regProduct.Close()
        regCompany.DeleteSubKey("JesterDevReg")
        ' Delete the Company key, after closing it.
        regCompany.Close()
        regSoftware.DeleteSubKey("JesterDev")

Edit: Here is the whole thing. Well more or less.

' Here we define the RegistryKey objects for the registry hives.
    'These arent all needed but I have them here as a refference for
    'you to use when needed in your own apps. 
    Dim regClasses As RegistryKey = Registry.ClassesRoot
    Dim regCurrConfig As RegistryKey = Registry.CurrentConfig
    Dim regCurrUser As RegistryKey = Registry.CurrentUser
    Dim regDynData As RegistryKey = Registry.DynData
    Dim regLocalMachine As RegistryKey = Registry.LocalMachine
    Dim regPerfData As RegistryKey = Registry.PerformanceData
    Dim regUsers As RegistryKey = Registry.Users
 
 
 
    'Define Variables for 'Write'
    Dim regSoftware As RegistryKey
    Dim regCompany As RegistryKey
    Dim regProduct As RegistryKey
 
'Here we will add company and product keys under HKEY_LOCALMACHINE\
        'HKEY_SOFTWARE.
 
        'First thing is to open the key.
        regSoftware = Registry.LocalMachine.OpenSubKey("SOFTWARE", True)
 
        'Add the key, or just open it if it alread exists.
 
        regCompany = regSoftware.CreateSubKey("JesterDev")
 
 
        'Add another key for the product name.. Or again, open it of it exists.
 
        regProduct = regCompany.CreateSubKey("JesterDevReg")
 
        'Create the three values under the product key in the hives.
 
        regProduct.SetValue("Path", "C:\AppPath\Bin")   ' a string value
        regProduct.SetValue("MajorVersion", 2)              ' a numeric value
        regProduct.SetValue("MinorVersion", 1)              ' a numeric value
 
        lblInfo.Text = "Values have been stored in the registry. It is advised that you delete them."
 
    End Sub
 
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
 
        ' Delete the three values just added.
        regProduct.DeleteValue("Path")
        regProduct.DeleteValue("MajorVersion")
        regProduct.DeleteValue("MinorVersion")
        ' Delete the Product key, after closing it.
        regProduct.Close()
        regCompany.DeleteSubKey("JesterDevReg")
        ' Delete the Company key, after closing it.
        regCompany.Close()
        regSoftware.DeleteSubKey("JesterDev")
 
        lblInfo.Text = "Reg Keys have been deleted. Wise move."
 
    End Sub

[Athley]

Is the regProduct variable dimmed at class level, as there is one function header missing from your code its impossible to tell?

It feels like it is but Im asking just to be sure.

[Jes|er]

Sorry about that. Yes it is dimmed at class level. I think I found the the problem however. If the reg keys are not present then an exception gets thrown.

From what I have read it shouldnt throw an exception if a reg value is null. Have some ideas on this?

[Athley]

Yes, I think I have read something similar. But If I remember correctly I think I had to check if the value where null or not before doing deletes. Can't get to my projects at work as Im home now, but I'll try to remeber to check this when I get back.